1. Field of the Invention
The present invention relates to a die changer truck for carrying a die assembly and/or a bladder assembly to a tire vulcanizer.
2. Description of the Related Art
A conventional tire vulcanizer to which this kind of die changer truck is applied will now be described with reference to FIG. 6.
As shown in FIG. 6, reference numeral 101 generally denotes a vertical type, hydraulic tire vulcanizer. The tire vulcanizer 101 has a frame consisting of a base frame 102, a pair of opposed side frames 103, and a top frame 104. A heat insulating plate 105 and a lower heating plate 106 are fixedly mounted on the base frame 102 by bolts or the like. A lower mold 107 is mounted on the lower heating plate 106. An upper mold 108 releasable from the lower mold 107 is fixed through an upper heating plate 109 and a heat insulating plate 110 to a slider 111. The slider 111 is connected to a vertical cylinder 112 supported to the top frame 104, so that the slider 111 can be vertically moved with the upper mold 108 by driving the vertical cylinder 112. Further, a pressure transmitting rod 113 is so provided as to stand from the slider 111, and a hollow pressing cylinder 114 is fixed to the top frame 104, so that a pressure can be transmitted from the hollow pressing cylinder 114 through a releasable half nut 115 to the pressure transmitting rod 113.
In the tire vulcanizer mentioned above, the die, or the lower mold 107 and the upper mold 108, must be occasionally changed in changing a tire size, in cleaning and repairing the die, etc. The change of the die is carried out in the following three steps. In the first step, the assembly of the lower mold 107 and the upper mold 108 is temporarily put on the lower heating plate 108. At this time, the slider 111 is kept in an upper limit position thereof. This first step is performed by using a forklift or the like. In the second step, the lower mold 107 is positioned with respect to the lower heating plate 108 and is fixed thereto. This second step is normally manually performed by a skilled operator operating a forklift or the like. Finally in the third step, the slider 111 is lowered, and the upper mold 108 is fixed to the upper heating plate 109 by bolts or the like.
Prior to the working of the first to third steps, it is necessary to remove an old bladder assembly mounted on a central mechanism 116 located at the center of the lower mold 107. Further, after the working of the first to third steps, a new bladder assembly must be mounted on the central mechanism 116. Such removal and mounting of the bladder assemblies are manually carried out, and transportation of the bladder assemblies is carried out by using a forklift or the like.
In this manner, transportation of the die assembly and the bladder assembly to be changed is carried out by using a forklift or the like, thus requiring a long time of die change and further requiring labor for manual operation of the die change. In particular, the tire industry has recently been entering the times of multi-item small-lot production like some other industries, resulting in an increase in frequency of the die change. Accordingly, if the die change spending much time is frequently carried out, the rate of operation of the tire vulcanizer is reduced and much labor is required.